Astronomy & Astrophysics

Table 1: y-distortion: $\Delta T=T_{\rm ref}\cdot y$ in $\mu$ K for y as given in the left column in some of the PLANCK spectral channels. Here $y_{\rm d}=2.6\times 10^{-7}$ , $y_{\rm opt, 0}=3~{y_{\rm d}}$ and $y_{\rm opt}=12~{y_{\rm d}}$ .